diff options
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c new file mode 100644 index 000000000..107be5546 --- /dev/null +++ b/mm/vmalloc.c @@ -0,0 +1,244 @@ +/* + * linux/mm/vmalloc.c + * + * Copyright (C) 1993 Linus Torvalds + */ + +#include <asm/system.h> + +#include <linux/signal.h> +#include <linux/sched.h> +#include <linux/head.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/malloc.h> +#include <linux/mm.h> + +#include <asm/segment.h> +#include <asm/pgtable.h> + +struct vm_struct { + unsigned long flags; + void * addr; + unsigned long size; + struct vm_struct * next; +}; + +static struct vm_struct * vmlist = NULL; + +static inline void set_pgdir(unsigned long address, pgd_t entry) +{ + struct task_struct * p; + + for_each_task(p) + *pgd_offset(p,address) = entry; +} + +static inline void free_area_pte(pmd_t * pmd, unsigned long address, unsigned long size) +{ + pte_t * pte; + unsigned long end; + + if (pmd_none(*pmd)) + return; + if (pmd_bad(*pmd)) { + printk("free_area_pte: bad pmd (%08lx)\n", pmd_val(*pmd)); + pmd_clear(pmd); + return; + } + pte = pte_offset(pmd, address); + address &= ~PMD_MASK; + end = address + size; + if (end > PMD_SIZE) + end = PMD_SIZE; + while (address < end) { + pte_t page = *pte; + pte_clear(pte); + address += PAGE_SIZE; + pte++; + if (pte_none(page)) + continue; + if (pte_present(page)) { + free_page(pte_page(page)); + continue; + } + printk("Whee.. Swapped out page in kernel page table\n"); + } +} + +static inline void free_area_pmd(pgd_t * dir, unsigned long address, unsigned long size) +{ + pmd_t * pmd; + unsigned long end; + + if (pgd_none(*dir)) + return; + if (pgd_bad(*dir)) { + printk("free_area_pmd: bad pgd (%08lx)\n", pgd_val(*dir)); + pgd_clear(dir); + return; + } + pmd = pmd_offset(dir, address); + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_SIZE; + while (address < end) { + free_area_pte(pmd, address, end - address); + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } +} + +static void free_area_pages(unsigned long address, unsigned long size) +{ + pgd_t * dir; + unsigned long end = address + size; + + dir = pgd_offset(&init_task, address); + while (address < end) { + free_area_pmd(dir, address, end - address); + address = (address + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } + invalidate(); +} + +static inline int alloc_area_pte(pte_t * pte, unsigned long address, unsigned long size) +{ + unsigned long end; + + address &= ~PMD_MASK; + end = address + size; + if (end > PMD_SIZE) + end = PMD_SIZE; + while (address < end) { + unsigned long page; + if (!pte_none(*pte)) + printk("alloc_area_pte: page already exists\n"); + page = __get_free_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + *pte = mk_pte(page, PAGE_KERNEL); + address += PAGE_SIZE; + pte++; + } + return 0; +} + +static inline int alloc_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size) +{ + unsigned long end; + + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_SIZE; + while (address < end) { + pte_t * pte = pte_alloc_kernel(pmd, address); + if (!pte) + return -ENOMEM; + if (alloc_area_pte(pte, address, end - address)) + return -ENOMEM; + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } + return 0; +} + +static int alloc_area_pages(unsigned long address, unsigned long size) +{ + pgd_t * dir; + unsigned long end = address + size; + + dir = pgd_offset(&init_task, address); + while (address < end) { + pmd_t *pmd = pmd_alloc_kernel(dir, address); + if (!pmd) + return -ENOMEM; + if (alloc_area_pmd(pmd, address, end - address)) + return -ENOMEM; + set_pgdir(address, *dir); + address = (address + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } + invalidate(); + return 0; +} + +void vfree(void * addr) +{ + struct vm_struct **p, *tmp; + + if (!addr) + return; + if ((PAGE_SIZE-1) & (unsigned long) addr) { + printk("Trying to vfree() bad address (%p)\n", addr); + return; + } + for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { + if (tmp->addr == addr) { + *p = tmp->next; + free_area_pages(VMALLOC_VMADDR(tmp->addr), tmp->size); + kfree(tmp); + return; + } + } + printk("Trying to vfree() nonexistent vm area (%p)\n", addr); +} + +void * vmalloc(unsigned long size) +{ + void * addr; + struct vm_struct **p, *tmp, *area; + + size = PAGE_ALIGN(size); + if (!size || size > high_memory) + return NULL; + area = (struct vm_struct *) kmalloc(sizeof(*area), GFP_KERNEL); + if (!area) + return NULL; + addr = (void *) VMALLOC_START; + area->size = size + PAGE_SIZE; + area->next = NULL; + for (p = &vmlist; (tmp = *p) ; p = &tmp->next) { + if (size + (unsigned long) addr < (unsigned long) tmp->addr) + break; + addr = (void *) (tmp->size + (unsigned long) tmp->addr); + } + area->addr = addr; + area->next = *p; + *p = area; + if (alloc_area_pages(VMALLOC_VMADDR(addr), size)) { + vfree(addr); + return NULL; + } + return addr; +} + +int vread(char *buf, char *addr, int count) +{ + struct vm_struct **p, *tmp; + char *vaddr, *buf_start = buf; + int n; + + for (p = &vmlist; (tmp = *p) ; p = &tmp->next) { + vaddr = (char *) tmp->addr; + while (addr < vaddr) { + if (count == 0) + goto finished; + put_fs_byte('\0', buf++), addr++, count--; + } + n = tmp->size - PAGE_SIZE; + if (addr > vaddr) + n -= addr - vaddr; + while (--n >= 0) { + if (count == 0) + goto finished; + put_fs_byte(*addr++, buf++), count--; + } + } +finished: + return buf - buf_start; +} |